Loggerhead sea turtle (
C. caretta
) is the official European bioindicator of marine litter in the Mediterranean Sea. In 2019, 8 sea turtles, out of 28 specimens loggerhead on the Adriatic coast of ...Molise, were subjected to necropsy. The intestinal contents were collected and the microplastics until 0.45 μm were extracted. Qualitative and quantitative assessments were performed by stereomicroscope observation and spectroscopic analyses (attenuated total reflection-Fourier transform infrared spectroscopy, ATR-FTIR and Raman microspectroscopy, RMS). Moreover, the analytical quantification of polyethylene terephthalate (PET), polycarbonate (PC), para phthalic acid (PTA) and bisphenol A (BPA) in fat and liver tissues was performed by LC-MS/MS. Microparticles ranging from 0.45 μm to 1 mm were found in all turtles, for a total of 623, while plastic litter greater than 1 mm were found only in 4 specimens (ranging from 0.03 to 0.11 g). Nineteen different polymers and 10 pigments, including polyester (100% of animals), high-density polyethylene (50%) and polypropylene (50%) were identified. BPA, PTA and PET were detected in fat and liver tissues of all animals, while PC was found only in 50%. A major prevalence was registered in the abdominal fat tissue, although only PC compounds were significantly higher in abdominal tissue (
p
< 0.05), except for free PTA with liver tissue being the most contaminated (
p
< 0.05). Microplastics and additives surely impact the health status of turtles that showed gastrointestinal impairment and an important level of contamination in tissues.
Graphical abstract
Both marine environment and biota are affected by microplastics, thus requiring a punctual and continuous monitoring of their presence and impacts. The number of studies analysing microplastics in ...vertebrates and invertebrates is continuously growing, but few generalizable patterns have been evidenced to date. This work explores some emerging hypotheses using data from four different fish species sampled in the same locality off Mediterranean central Tyrrhenian coasts: if ingestion rate in fish can be affected by both species-specific feeding preferences and vertical distribution; and if a relationship between fish size and abundance of ingested microplastics occurs. The results obtained showed no significant differences in the microplastics quantity recorded in pelagic, benthopelagic or demersal species. However, our data suggest that predator species may be attracted by microplastics similar to their natural prey for colour, since the piscivorous Mediterranean horse mackerel (Trachurus mediterraeus) showed a significant relationship between size and blue fibres. More broadly, our findings evidenced a correlation among fish size and both fibres and films ingested. A comparison of the microplastics occurrence reported across the Mediterranean Sea for the same species showed deep differences which can be explained by both the uneven concentration of microplastics across the basin and the different recovery methods used in the various studies.
•High occurrence of microplastics recorded in 4 fish species form Mediterranean Sea.•No difference in microplastics ingested by pelagic, benthopelagic or demersal fish.•A correlation among fish size and both fibres and films ingested was observed.•Predator species tend to ingest microplastics similar to their prey for colour.•The method used to recover microplastics impacts the results: harmonization needed.
Sea turtles are considered as bio-indicators for monitoring the efficiency of restoration measures to reduce marine litter impacts on health. However, the lack of extended and standardised empirical ...data has prevented the accurate analysis of the factors influencing litter ingestion and the relationships with individual health. Historic data collected from 1988 and standard data collected from 2016 were harmonised to enable such analyses on necropsied loggerhead turtles (Caretta caretta) in eight Mediterranean and North-East Atlantic countries. Litter was found in 69.24 % of the 1121 individuals, mostly single-use and fishing-related plastics. Spatial location, sex and life history stage explained a minor part of litter ingestion. While no relationships with health could be detected, indicating that all individuals can be integrated as bio-indicators, the mechanistic models published in literature suggest that the high proportion of plastics in the digestive contents (38.77 % per individual) could have long-term repercussions on population dynamics.
•Loggerheads highly impacted whatever the body condition and growth stage.•High rate of ingested plastics regarding food augurs long term repercussions.•Spatial variations in litter ingestion reflect different risks among areas.•All individuals can be considered as indicator for monitoring litter impacts.
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